I'm was planning to get Semoque 620 or 630. Both are great brushes but what the difference. 620 is for face lathering and 830 is for bowl lathering. They both great for shaving cream and soap. Can both model can use face and bowl lathering at the same time? I'm watching an YouTube from Busta and he using comparison these two. I sometimes use shaving soap and sometimes use the cream. My new favorite shaving products are D.R. Harris. They are the best. Lathering is very quickly.

I don't think there is any difference between a brush for soaps and a brush for creams. Where I think there is a difference is when it comes to face-lathering vs bowl-lathering. Both brushes that you named will work for soaps, creams, face-lathering, and bowl-lathering.

The 830 (as does the 1305) has a special quality of boar bristle that I like better than any other I have tried. This brush would work very well for both face-lathering and bowl-lathering. I have not used the 620, myself, but from what I have read it would be a shorter-lofted and stiffer brush, with a different grade of boar bristle than that in the 830. If this is the case, the 830 might be easier on sensitive skin than the 620. The 620 is usually chosen by face-latherers who want a stiffer brush.

If you want to face-lather and bowl-lather, and you have sensitive skin, I think you would be happier with the 830.

- Murray

PS. I'm of the impression that you are trying to solve a number of shaving issues by constantly changing equipment. A new brush will add to the variety of your shaving experience, but it won't solve the problem of repeated nicks you report getting when you shave. You will need to further develop your technique to accomplish that.